MXPA00002588A - Fault current limiting superconducting coil - Google Patents

Abstract

A superconducting coil (10) includes a first superconductor (18) formed of an anisotropic superconducting material for providing a low-loss magnetic field characteristic for magnetic fields parallel to the longitudinal axis of the coil (10) and a second superconductor (22) having a low loss magnetic field characteristic for magnetic fields perpendicular to the longitudinal axis of the coil (10). The first superconductor (18) has a normal state resistivity characteristic conductive for providing current limiting in the event that the superconducting magnetic coil (10) is subjected to a current fault.

Description

SUPERCONDUCTOR COIL THAT LIMITS THE FAILURE CURRENT BACKGROUND OF THE INVENTION The invention relates to magnetic superconducting coils. An important property of a superconductor is the disappearance of its electrical resistance when it cools down from a critical temperature Te. Below Te and for a given superconductor, there is a maximum amount of current, called the critical current (le) of the superconductor, which can be carried by the superconductor to a specific magnetic field and temperature. Any current greater than that makes it start the resistance in the superconductor. If the superconductor is inserted or wound with a conductive matrix, any current increase above it will be shared between the superconductor and the matrix material based on the start of the resistance in the superconductor. Superconducting materials are generally classified as either high or low temperature superconductors. High temperature superconductors (HTS) such as those made of ceramic or metal oxides are commonly anisotropic, which means that they generally conduct better, relative to the crystal structure, in one direction than in another. Additionally, it has been observed that, due to this anisotropic characteristic, the critical current varies as a function of the orientation of the magnetic field with respect to the crystallographic axes of the superconducting material. The high-temperature anisotropic superconductors include, but are not limited to, the family of Cu-O-based ceramic superconductors, such as the members of the rare-copper-earth-rare earth (YBCO) family, the family of copper-calcium-barium-thallium oxide (TBCCO), the copper-calcium-barium-mercury oxide (HgBCCO) family, and the copper-calcium-strontium-bismuth (BSCCO) family. These compounds can be adulterated with stoichiometric amounts of lead or other materials to improve their properties (for example, (Bi, Pb) 2Sr2Ca2Cu3 ?? o). The anisotropic high temperature superconductors are commonly manufactured in the form of a superconducting tape having a relatively high aspect ratio (ie, width greater than thickness). The thin ribbon is manufactured as a multi-filament composite superconductor that includes individual superconducting filaments that extend substantially the length of the multi-filament composite conductor and that are surrounded by a matrix-forming material (eg, silver). The ratio of superconductive material to matrix-forming material is known as the "fill factor" and is generally less than 50%. Although the matrix-forming material conducts electricity, it is not superconducting. Together, the superconducting filaments and the matrix-forming material form the conductor composed of multiple filaments. High temperature superconductors can be used to make magnetic superconducting coils such as solenoids, magnets on racetracks, multiple magnets, etc. , in which the superconductor is wound in the form of a coil. When the temperature of the coil is sufficiently low that the conductor of high temperature superconductors can exist in a superconducting state, the current carrying capacity as well as the magnitude of the magnetic field generated by the coil is significantly increased. High-temperature superconductors have been used as current limiting devices to limit the flow of excessive current in electrical systems produced for example, short circuits, lightning, or common power fluctuations. The current limiting devices of the high temperature superconductors can have a variety of different configurations including inductive and resistive current limiters. BRIEF DESCRIPTION OF THE INVENTION The invention shows a superconducting magnetic coil having a first superconductor formed of an anisotropic superconducting material to provide a low loss magnetic field characteristic for magnetic fields parallel to the longitudinal axis of the coil and a second superconductor that has a low loss magnetic field characteristic for magnetic fields perpendicular to the longitude axis of the coil (for example, when the orientation of an applied magnetic field is perpendicular to the widest surface of a superconducting belt, as opposed to when the field is parallel to this wider surface). In the embodiments, the first superconductor has a conductive normal state resistivity characteristic to provide current limiting in the event that the superconducting magnetic coil is subjected to a current fault. In a general aspect of the invention, the first superconductor is wound around the longitudinal axis of the coil and is formed of an anisotropic superconducting material having a first characteristic of resistivity in a normal state of operation; and a second superconductor, wound around the longitudinal axis of the coil and connected to the first anisotropic superconductor, which has a second resistivity characteristic, in a normal state of operation, lower than the resistivity characteristic of the first anisotropic superconductor in a normal state of operation. Among other advantages, the first superconductor has a resistivity characteristic so that, if it loses its superconducting properties (for example, due to an increase in current) and returns to its normally conductive state, the first superconductor limits the current in a resistive way that flows through the coil, thus avoiding damage to itself, the second superconductor, and other components connected to the magnetic superconducting coil. Thus, in one application, the magnetic superconducting coil provides reliable protection in the event of a power failure by limiting the current flowing through the coil for a sufficient period of time to allow a circuit breaker to trip or The fuse is melted, thus preventing additional current flow and potential catastrophic damage to the magnetic superconducting coil and other system components. During normal superconducting operation, the coil has a low loss that allows for greater current handling capacity. In another aspect of the invention, a first anisotropic superconductor is wound around the longitudinal axis of the coil and is formed as a superconducting tape, the first anisotropic superconductor is configured to provide a low AC loss characteristic in the presence of parallel magnetic fields to the wide surface of the superconducting tape; and a second superconductor, different from the first anisotropic superconductor. The second superconductor is wound around the longitudinal axis of the coil and is connected to one end of the first anisotropic superconductor and configured to provide a low AC loss characteristic in the presence of magnetic fields perpendicular to the wide phases of the superconductive tape of the first anisotropic superconductor . The embodiments of the above described aspects of the invention may include one or more of the following characteristics.

The second superconductor is connected to one end of the first anisotropic superconductor and is configured to provide a low alternating current loss characteristic in the presence of perpendicular magnetic fields. The second superconductor is an anisotropic material and is in the form of a ribbon. The first anisotropic superconductor is in monolithic form (ie, in the form of a monofilament or a group of closely spaced multiple filaments that are electrically and completely coupled together, acting as a monofilament). Alternatively, the tape of the first anisotropic superconductor in monolithic form includes a multi-filament composite superconductor having individual superconducting filaments that extend the length of the multi-filament composite superconductor. The multi-filament composite superconductor has a resistivity characteristic, in its normal state, in a range between about 0.1 to 100 μi-cm, preferably 5 to 100 μO-cm. The first anisotropic superconductor may also be in the form of a superconducting tape and generally has an aspect ratio in a range between about 5: 1 and 1000: 1. The first anisotropic superconductor may include a support strip formed of a thermal stabilizer having a resistivity characteristic greater than about 1 μO-cm.

The second anisotropic superconductor may be a tape having a superconductor composed of multiple filaments with individual superconducting filaments extending the length of the superconductor composed of multiple filaments and surrounded by a matrix-forming material. The first and second anisotropic superconductors may be wound in a layered configuration. Alternatively, the first and second anisotropic superconductors are formed of single or double flat coils, each coil electrically connected to an adjacent coil. In an alternative embodiment, the first and second anisotropic superconductors are wound in a "spliced configuration". With this configuration, a first segment of the first anisotropic superconductor extends along the longitudinal axis in a first direction towards the second anisotropic superconductor and is connected to a first end of a first segment of the an isotropic superconducting second segment at a first junction. . A second end of the first segment is connected to a second segment of the first anisotropic superconductor, the second segment extends along the longitudinal axis in a second direction away from the second anisotropic superconductor. The first and second superconductors are sotropic, and they have ducts of high temperature. In certain modalities, the second perconductor constitutes a portion of the total amount of the superconductor in the coil in a range between approximately 5% and 30%, for example, 10%. Other advantages and aspects will be apparent from the following description and claims. DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional side view of a superconducting coil of the invention having "flat" coils. Figure 2 is a cross-sectional side view of a superconducting coil of Figure 1 having "flat" coils. Figure 3 is a side view of the superconducting ribbon associated with a central region of the superconducting coil of Figure 1. Figure 4 is a side view of the superconducting ribbon of Figure 3 having a laminated thermal support layer . Figure 5 is a cross-sectional view of a multi-filament composite conductor associated with the end regions of the superconducting coil of Figure 1. Figure 6 is an enlarged perspective view of a multi-strand cable for the composite conductor of multiple filaments of Figure 5. Figure 7, is a perspective view of an alternative superconducting coil of the invention. Figure 8 is a cross-sectional view of a portion of another superconductive coil of the invention. Figure 9 is a cross-sectional side view of a portion of a transformer having a superconducting coil of the invention. Figure 10 is a plane showing the radial coil field RMS as a function of the percentage of the axial coil length. DESCRIPTION With reference to Figure 1, a high-performance, mechanically robust superconducting coil assembly 5 includes an iron core 6 and a superconducting coil 8 having a central region 1 1 and end regions 14. As will be discussed further detailed below, the superconducting material used to form the central region 1 1 has characteristics different from those used to form the end regions 14. In particular, the central region 1 1 is formed with a conductor 18 (Figure 3) having a low loss characteristic in its superconducting state, but in its normal state it has a relatively high resistivity characteristic, so that the central region 1 1 serves as a current limiting section of the coil assembly 10. Therefore, in the case of an electrical power failure, the conductor 18 reverses its normal, non-superconducting state for a sufficient time to prevent the assembly of coil 10 is damaged due to overheating. During the time that the current is limited by the driver in its normal state! , a circuit breaker or fuse can be used to open the circuit and prevent additional current flow.

The end regions 14 are formed of a conductor 22 (Figure 5) which, unlike the conductor 18 of the central region 1 1, is configured to provide a low alternating current loss characteristic in the presence of perpendicular magnetic fields. The conductor 22 is configured in this way because the lines of the magnetic field emanating from the superconducting magnetic coil assembly 10 in the end regions 14 become perpendicular with respect to the plane of the conductor 22 (the plane of the conductor is parallel to the wide surface of the superconducting tape) causing the critical current density in these regions to fall significantly. In fact, the critical current reaches a minimum when the magnetic field is oriented perpendicularly with respect to the plane of the conductor. With reference to Figure 2, in one embodiment, a superconducting coil 10 includes a central region 1 1 and an end region 14 formed with interconnected double "flat" coils 12a, 12b. The central region 1 1 is shown here having seven separate double flat sections 12a and each end region 14 is shown having a single single flat section 12b. Each double "flat" coil 12a, 12b has co-winding superconductors wound in parallel which are then stacked coaxially one above the other, with adjacent coils separated by an insulating layer 16. An internal support tube 17 supports the coils of the central region 1 1 and the end regions 14 with end members 20 attached to opposite ends of the inner support tube 17 for compressing the coils of the central region 1 1 and the end regions 14. The internal support tube 17 and the members of . { 0P extreme 20 are manufactured from a non-magnetic material, electrically insulator, such as aluminum or plastic (for example, G-10). With reference to Figure 3, each double flat coil 12a of the conductor 18 is made of an anisotropic superconductor of high temperature superconductors formed in the form of a thin ribbon that allows to bend the conductor in diameters relatively small and allows to increase the winding density of the coil. A method for manufacturing double superconducting flat coils with superconducting tape of this type is disclosed in U.S. Patent Serial Number 5, 531, 015, assigned herein. assignee, and incorporated herein by reference. The conductor 18 is relatively long and has a relatively large aspect ratio in a range between about 5: 1 and 1000: 1. For superconducting tapes formed from the BSCCO family, the aspect ratio is generally between approximately 5: 1 and 20: 1 while for tapes formed from the YBCO family, the aspect ratio is generally between about 100: 1 and 1000: 1, commonly about 400: 1. The conductor 18 is monolithic in shape, which means that the anisotropic superconductor of high superconductors The temperature is in the form of a monofilament 15 or a group of closely spaced multi-filaments that are electrically and completely coupled together, acting as a monofilament. The monolithically shaped conductor 18 is not affected in the same manner as the conductor 22 in the end regions 14 and provides a relatively low alternating current loss characteristic because the magnetic fields are substantially parallel along the axis of the central region eleven .

The monolithically shaped conductor 18 may be a material of the rare earth copper-oxide (YBCO) family such as that described in the U.S. Patent of North America Serial No. 5,231,074 of Cima and co-inventors, entitled "Preparation of Highly Texturized Oxide Superconductive Films from MOD Precursor Solutions" which is incorporated herein by reference. Alternatively, the conductor 18 can be formed of other Cu-O based ceramic superconductors, such as the copper calcium strontium bismuth (BSCCO) family which is commonly in the form of a compound of individual superconducting filaments surrounded by a forming material of matrix. A description of these composite superconductive tapes is disclosed in U.S. Patent No. 4,051,015. With reference to FIG. 4, the conductor 18 is laminated to a thermal stabilizing support strip 19 formed, for example. , stainless steel, nickel or other suitable alloy As the resistive heating in the conductor 18 can be high, the support strip 19 serves as a heat sink to maintain the temperature of the conductor 18 at a safe level while also providing a path of high strength for current to flow through coil assembly 10. Support strip 19 has a resistivity characteristic greater than about 10 μO-cm. When the conductor 18 is formed of the YBCO material, substantially all of the current flows through the support strip 19. On the other hand, when using a composite superconducting material (eg, formed of BSCCO) the current can also flow through. of the composite matrix material having a resistivity characteristic in a range between approximately 0.1 to 100 μO-cm. The end regions 14 are also formed of a high temperature superconductor, but of a different material than that used to wind the central region 1 1. Although isotropic superconducting materials may be used, in many applications, anisotropic superconductors, such as the BSCCO type composite superconductor, are preferred. With reference to Figures 5 and 6, the end regions 14 do not have a monolithic shape. Instead, conductor 22 is a thin ribbon 24 made of a multi-filament composite superconductor having individual superconductive filaments 27 that extend substantially the length of the multi-filament composite condi- tion and are surrounded by a matrix-forming material 28. , commonly silver or other noble metal. In other embodiments, the aspected multiple filament yarns may be combined and are preferably braided, for example, in the manner shown in the illustration of a multi-stranded cable 28 (Figure 6). Braiding the individual multi-filament yarns and separating them with a matrix material having a high resistivity characteristic is important to provide the characteristic of low alternating current loss in the presence of perpendicular magnetic fields. The details concerning the types of superconductors and their manufacturing methods suitable for use in driver training 22 are described in the pending application with the present Serial Number 08/444, 564 filed on May 19, 1995 by GL Snitchler. , G. N. Riley, Jr., A. P. Malozemoff and C.J. Christopherson, entitled "Novel Fabrication Method and Structure for Improving Filament Coupling Losses in Superconducting Oxide Composites", assigned to the assignee of the present invention, and incorporated herein by reference. Other superconductors and their manufacturing methods are also described in the pending application with the present Serial Number 08 / 554,814 filed on November 7, 1995 by G. L. Snitchler, J. M. Seuntjens, W. L. Barnes and G. N. Riley, entitled "Wired Conductors Containing Anisotropic Superconducting Compounds and Method for Forming Them," assigned to the assignee of the present invention, and incorporated into the same by reference. The pending application with the present Serial No. 08/719, 987 filed on September 25, 1995, entitled "Decoupling of Superconducting Filaments in High Temperature Superconducting Compounds", assigned to the assignee of the present invention, and incorporated herein by reference also discloses methods for manufacturing superconducting wires suitable for the conductor 22. In certain applications, the superconducting filaments and the matrix-forming material are enclosed in an insulating layer 30. When the anisotropic superconducting material is formed in a tape, the critical current is generally less when the orientation of an applied magnetic field is perpendicular to the wider surface of the tape, in contrast to when the field is parallel to this wider surface. The conductor 22 of the end regions 14 has a resistivity characteristic, in its normal state, smaller than that of the conductor 18 of the central region 1 1. Referring again to Figure 2, electrical connections consisting of short lengths of conductive metal 34, such as silver, for joining or splicing the individual coils together in a series circuit. The individual coils can also be connected using conductive welding. In certain applications, short lengths of splicing material can be formed of superconducting material. A length of superconducting material (not shown) also connects one end of the coil assembly 10 to a terminating post placed on the end member 20 to supply current to the coil assembly 10. It is assumed that the current flows in a contrary direction to the clock hands with the vector of the magnetic field 26 being generally normal to the end member 18 (in the direction of the longitudinal axis 31) forming the upper part of the coil assembly 10. Although the above described modality in conjunction with the Figure 2 uses flat type coils, other configurations are within the scope of the claims. For example, with reference to Figure 7, a superconducting coil 40 includes a central region 42 wound with a tape 44 formed of an anisotropic superconducting material in a layered configuration. In a layered configuration, the tape 44 is wound along a longitudinal axis 46 of the coil 40 from one end of the coil 40 with successive windings wound after the preceding winding until the opposite end of the coil 40 is reached, thus forming a first layer of the coil. Then, the belt 44 is wound back along the axis 46 in the opposite direction and on the first layer of the coil. This winding approach is repeated until the desired number of turns is wound on coil 40. The end regions 48 can be wound as a single or double flat coil in the manner described above with reference to Figure 2, or can be wind in a layered configuration. The end regions 48 are connected to the central region 42 using metal or solder connections.

With reference to Figure 8, in another embodiment, a superconducting coil 50 includes a central region 52 formed of high temperature anisotropic superconducting material wound in a layered configuration. However, unlike the coil 40 of Figure 3, the central region 50 is formed of individual lengths 54a, 54b, 54c of high temperature anisotropic superconducting material. Each section 54a, 54b, 54c is spliced (e.g., using conductive metal or weld joints) in the end regions 56 to corresponding portions 58a, 58b, 58c of high temperature anisotropic superconducting material having the current density conductor less. With reference to Figure 9, a superconducting transformer 60 includes a low voltage (high current) coil 62 and a high voltage (low current) coil 64, each wound around iron cores (not shown) and in polymer tube ways 66. In this embodiment, the low voltage coil 62 has four layers while the high voltage coil has 20 layers. Each coil 62, 64 is contained in a cryogenic vessel (not shown) containing liquid nitrogen with the iron cores held at room temperature so that the heat generated by the energy dissipated in the cores is not transferred to the cryogenic vessel. In conjunction with the above description, the low voltage coil 62 and the high voltage coil 64 include the central region 66, 68 to provide current limitation, as well as the end regions 70, 72, respectively, to maintain performance. of low alternating current loss in the presence of perpendicular magnetic fields in the end regions. Depending on the particular application, each transformer design may have a different configuration of superconductors used for the central regions 66, 68 and end regions 70, 72. In a 30 MVA transformer mode, the end regions 70, 72 include 24 turns (12 at each end) of the conductor while 51 turns of current limiting wire are provided for the central regions 66, 68.

With reference to Figure 10, a plane illustrating the radial coil field RMS (Tesla units) as a function of the percentage of the axial length of the coil, indicates that the radial magnetic field is almost non-existent in the central region of the coils. coils and increases dramatically in the extreme regions. Therefore, the wire-limiting wire in monolithic form is generally provided only in the central regions 66, 68 where the radial magnetic field is low. The relative behavior of a transformer with and without low loss end regions is presented in the table below. The alternating current losses of a transformer having end regions 14 with the conductor 22 can be made with a lower aspect ratio wire to somehow reduce the losses. The case of the low aspect monolith shown in Table 1, has a change in the aspect ratio of the end windings of a factor of about four. Therefore, for certain applications, the transformer may include a conductor 22 having a monolith of low aspect ratio.

Claims (12)

1. CLAIMS I.A superconducting magnetic coil for generating a magnetic field that varies along a longitudinal axis of the coil, the coil comprises: a first superconductor wound around a longitudinal axis of the coil, the first superconductor is formed of a material anisotropic superconductor having a first characteristic of resistivity in a normal state of operation; and a second superconductor wound around the longitudinal axis of the coil and connected to the first anisotropic superconductor, the second superconductor has a second resistivity characteristic, in a normal state of operation, smaller than the resistivity characteristic of the first anisotropic superconductor in a normal state of operation. The magnetic superconducting coil of claim 1, wherein the second superconductor is connected to one end of the first anisotropic superconductor and is configured to provide a low alternating current loss characteristic in the presence of perpendicular magnetic fields. 3. The superconducting magnetic coil of claim 2, wherein the second superconductor is formed of an anisotropic superconducting material. 4. The superconducting magnetic coil of claim 3, wherein the first anisotropic superconductor is in the form of a superconducting tape. 5. The superconducting magnetic coil of claim 4, wherein the first anisotropic superconductor tape is in monolithic form. 6. The superconducting magnetic coil of claim 5, wherein the first anisotropic superconductor tape in monolithic form is in the form of a monofilament superconductor. 7. The superconducting magnetic coil of claim 5, wherein the first anisotropic superconductive tape in monolithic form includes a multi-filament composite superconductor having individual superconducting filaments that extend the length of the multi-filament composite superconductor. The superconducting magnetic coil of claim 7, wherein the first resistivity characteristic, in its normal state, is in a range of 10 to 50 μO-cm. 9. The superconducting magnetic coil of claim 4, wherein the superconducting tape has an aspect ratio of a range between about 200: 1 and 500: 1. 10. The superconducting magnetic coil of claim 4, wherein the superconducting tape includes a support strip formed of a thermal stabilizer. The magnetic superconducting coil of claim 10, wherein the support strip has a resistivity characteristic of greater than about 10 μO-cm. 12. The superconducting magnetic coil of claim 3, wherein the second anisotropic superconductor is formed as a superconducting tape. The magnetic superconducting coil of claim 12, wherein the superconducting ribbon of the second anisotropic superconductor includes a multi-filament composite superconductor having individual superconducting filaments that extend the length of the superconducting composite of multiple filaments and are surrounded by a material matrix former. The superconducting magnetic coil of claim 1, wherein the individual superconducting filaments of the second anisotropic superconductor are stranded. The magnetic superconducting coil of claim 3, wherein the first superconductor is wound in a layered configuration. 16. The superconducting magnetic coil of the claim 3, where the first supercond uctor is formed of flat coils, each coil is electrically connected to an adjacent coil. The magnetic superconducting coil of claim 16, wherein the first superconductor is formed of double flat coils. The magnetic superconducting coil of claim 3, wherein the second its perconductor is wound as a flat coil. 1 9. The superconducting magnetic coil of claim 1 5, wherein the second superconductor is wound as a flat coil. 20. The superconducting magnetic coil of the claim 1 6, wherein the second anisotropic superconductor is wound as a flat coil. twenty-one . The magnetic superconducting coil of claim 3, wherein a first segment of the first superconductor extends along the longitudinal axis in a first direction toward the second superconductor and is connected to a first end of the second superconductor at a first junction, a Second end of the first segment is connected to a second segment of the first superconductor, the second segment extends along the longitudinal axis in a second direction remote from the second superconductor. 22. The superconducting magnetic coil of the claim 3, wherein the first and second superconductors are high temperature superconductors. 23. The superconducting magnetic coil of claim 3, wherein the first superconductor constitutes more than 50% of the total amount of the superconductor of the coil. 24. The superconducting magnetic coil of claim 3, wherein the second superconductor constitutes a portion of the total amount of its per- conductor of the coil in a range between 5% and 30% 25. The magnetic superconducting coil of claim 24 , wherein the second superconductor constitutes approximately 10% of the total amount of the superconductor of the coil. 26. A superconducting magnetic coil for generating a magnetic field that varies along a longitudinal axis of the coil, the coil comprising: a first anisotropic superconductor wound around the longitudinal axis of the coil and formed as a superconducting ribbon having a wide surface, the first anisotropic superconductor is configured to provide a low alternating current loss characteristic in the presence of magnetic fields parallel to the broad surface of the superconducting belt; and a second superconductor, different from the first anisotropic superconductor and wound around the longitudinal axis of the coil, the second superconductor is connected to one end of the first anisotropic superconductor and configured to provide a characteristic of low alternating current loss in the presence of perpendicular magnetic fields to the broad surface of the superconducting ribbon of the first anisotropic superconductor. 27. The superconducting magnetic coil of claim 25, wherein the second superconductor is formed of an anisotropic superconducting material. 28. The superconducting magnetic coil of claim 27, wherein the first anisotropic superconductor tape is in monolithic form. 29. The superconducting magnetic coil of the claim 28, wherein the first anisotropic superconductor tape in monolithic form is in the form of a monofilament superconductor. 30. The magnetic superconducting coil of the claim 28, wherein the first anisotropic superconductor tape in monolithic form includes a multi-filament composite superconductor having individual superconducting filaments that extend the length of the multi-filament composite superconductor. 31 The superconducting magnetic coil of the claim 30, wherein the multi-filament composite superconductor has a resistivity characteristic, in its normal state, in a range between about 10 to 50 μO-cm. 32. The superconducting magnetic coil of the claim 26, wherein the superconducting tape has an aspect ratio of a range between about 200: 1 and 500: 1. 33. The superconducting magnetic coil of claim 26, wherein the superconducting tape includes a support strip formed of a stabilizer. thermal. 34. The superconducting magnetic coil of claim 33, wherein the support strip has a resistivity characteristic greater than about 10 μO-cm. 35. The superconducting magnetic coil of claim 26, wherein the second anisotropic superconductor is formed as a superconducting tape. 36. The superconducting magnetic coil of the claim 35, wherein the superconducting ribbon of the second anisotropic superconductor includes a multi-filament composite superconductor having individual superconducting filaments that extend the length of the superconducting composite of multiple filaments and are surrounded by a matrix-forming material. 37. The superconducting magnetic coil of the claim 36, wherein the individual superconductive filaments of the second anisotropic superconductor are stranded. 38. The superconducting magnetic coil of claim 26, wherein the first superconductor is wound in a layered configuration. 39. The magnetic superconducting coil of claim 26, wherein the first superconductor is formed of flat coils, each coil being electrically connected to an adjacent coil. 40. The superconducting magnetic coil of claim 39, wherein the first superconductor is formed of double flat coils. 41 The magnetic superconducting coil of claim 26, wherein the second superconductor is wound as a flat coil. 42. The superconducting magnetic coil of claim 38, wherein the second superconductor is wound as a planar coil. 43. The superconducting magnetic coil of the claim 38, wherein the second anisotropic superconductor is wound as a flat coil. 44. The superconducting magnetic coil of the claim 26, wherein a first segment of the first superconductor extends along the longitudinal axis in a first direction toward the second superconductor and is connected to a first end of the second superconductor at a first junction, a second end of the first segment is connected to a second segment of the first superconductor, the second segment extends along the longitudinal axis in a second direction away from the second superconductor. 45. The superconducting magnetic coil of claim 26, wherein the first and second superconductors are high temperature superconductors. 46. The superconducting magnetic coil of claim 26, wherein the first superconductor constitutes more than 50% of the total amount of the superconductor of the coil. 47. The superconducting magnetic coil of the claim 26, wherein the second superconductor constitutes a portion of the total amount of the superconductor of the coil in a range between 5% and 30%. 48. The superconducting magnetic bobbin of claim 47, wherein the second superconductor contains approximately% of the total superconductor amount of the coil.